second C linkage of overloaded function 'function' not allowed
More than one overloaded function is declared with C linkage. When using C linkage, only one form of a specified function can be external. Since overloaded functions have the same undecorated name, they cannot be used with C programs. The following sample generates C2733:
extern "C" { void F1(int); } extern "C" { void F1(void); } // C2733, delete one of the external linkages to resolve void main() { }